1. Field of the Invention
The present invention relates to a heating and oil-producing apparatus, such as a melting furnace for producing oil from a raw material, and a heating and oil-producing method.
2. Description of the Related Art
A heating and oil-producing apparatus such as a melting furnace for heating a waste plastic or like raw material to product oil, for example, as disclosed in patent document 1, has been conventionally known. The apparatus disclosed in this patent document 1 is provided with a container 100 for storing a molten plastic that functions also as heat transferring oil as shown in FIG. 8, and a heating chamber 102 for heating the container 100 from below using a combustion gas from a burner 101 is disposed below the container 100. U-shaped heat transferring pipes 103 communicating with the heating chamber 102 are arranged in the container 100, and the combustion gas from the heating chamber 102 flows from a lower side toward an upper side in the heat transferring pipes 103. Thus, the molten plastic at the bottom of the container can be heated by the higher-temperature combustion gas flowing at the lower parts of the heat transferring pipes 103, thereby promoting a natural convection of heat transferring oil 105.    Patent Document 1: Japanese Unexamined Patent Publication No. H11-323350.
However, since the natural convection occurs only around the heat transferring pipes 103 in the conventional heating and oil-producing apparatus, the heat transferring oil 105 distant from the heat transferring pipes 103 is likely to stay still. Thus, there still remains a room for improvement in heating efficiency in the container 100 although the natural convection is created in part of the container 100.